Science & Tech

Spotting a Liar: John Wayne Gacy

John Douglas

Lesson time 12:25 min

John Wayne Gacy was a notorious liar—as well as a serial killer who raped, tortured, and murdered at least 33 young men and boys. In this lesson, John deep dives into Gacy’s compulsive mendacity, and lays out ways to read someone’s behavior to determine if they’re being untruthful.

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Topics include: Never Trust a Polygraph • Identifying Deceptive Tactics • Case Study: Interviewing Gacy •.Tools for Detecting Lies and Deceptions • Assignment


[MUSIC PLAYING] - It's very difficult to discern whether or not a serial killer is lying. People have often asked me when you interview these criminals, they are some of the worst criminals ever known-- career conmen and serial murderers. So how do you know they're telling you the truth? And I said the reason I know is because before I do any kind of interview like that, I am armed with information. I will know the case backwards and forwards. But some people are just very, very good liars. [MUSIC PLAYING] In this chapter, we're going to be looking at lies and deception. Often that's where mistakes are made. It could be looking for body language and different signs, or eye evasiveness, or looking down, or rigid personality, or posture. And that's not always the case with him. Specifically, we're going to be looking at one very, very notorious killer, John Wayne Gacy. [MUSIC PLAYING] Lie detector tests-- I'm against them. I'm really against them. If you're thinking that people are going to respond like you respond, no way. In my experience, many serial killers like Ted Bundy and the Green River Killer have passed polygraph tests over and over again. The theory behind a polygraph is when people are lying, they experience a different emotional state than when they are telling the truth. Their heart rate increases. They sweat more, or their breathing changes. These are all physical signs of anxiety that are difficult for the body to hide, but some people can. One of the key factors with the psychopathic personality is really the lack of anxiety. They don't have the anxiety. Their heart doesn't race, you know, like yours would. But whatever the crime may be, they may feel it's justified. And because they feel like the crimes are justified, they don't show these signs of anxiety and nervousness in a polygraph test. [MUSIC PLAYING] The other thing I don't like about with the polygraph is that, if you're doing an investigation, you're telling the person that you really don't have any information. Because if you had information, why the hell do you want a polygraph me? So I'm really-- I'm not in favor of polygraphs. [MUSIC PLAYING] John Wayne Gacy is responsible for the death of at least 33 victims. 29 of them were buried on his property. [MUSIC PLAYING] And he was married. He was married two times. And then they broke up because he told his wife that he was bisexual, so she, you know, she left him and took the-- took the kids. And even when his wife was living there, she could smell the smell of decomposition of the bodies. And he said it was because of water problems-- sewer problems that they were having, you know, in the crawl space. He had a job where he was in home improvement, you know, fixing up houses, remodeling drugstores. Part of his side job was be a clown. He'd get dressed up as clown. He'd perform at different charitable events or someone's birthday party. ...

About the Instructor

Netflix’s “Mindhunter” was inspired by the FBI’s first criminal profiler, John Douglas. As chief of the National Center for the Analysis of Violent Crime, he conducted groundbreaking interviews with notorious criminals such as Charles Manson and Ed Kemper, changing interrogative tactics forever. On MasterClass, he teaches you to use his methods in everyday life, unlocking your intuition to read people's motives.

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John Douglas

Legendary Special Agent John Douglas teaches how criminal profiling methods can help you predict people’s motives to benefit your everyday life.

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